Molten metal reactor utilizing molten metal flow for feed material and reaction product entrapment

ABSTRACT

A molten metal reactor ( 10 ) quickly entrains a feed material in the molten reactant metal ( 16 ) and provides the necessary contact between the molten reactant metal and the feed material to effect the desired chemical reduction of the feed material. The reactor ( 10 ) includes a unique feed structure ( 24 ) adapted to quickly entrain the feed material into the molten reactant metal ( 16 ) and then transfer the molten reactant metal, feed material, and initial reaction products into a treatment chamber ( 12 ). A majority of the desired reactions occur in the treatment chamber ( 12 ). Reaction products and unspent reactant metal are directed from the treatment chamber ( 12 ) to an output chamber ( 14 ) where reaction products are removed from the reactor. Unspent reactant metal ( 16 ) is then transferred to a heating chamber ( 15 ) where it is reheated for recycling through the system.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to U.S. Provisional Patent Application Ser.No. 60/271,825 filed Feb. 27, 2001 and entitled “MOLTEN METAL REACTORUTILIZING MOLTEN METAL FLOW FOR FEED MATERIAL AND REACTION PRODUCTENTRAPMENT.” The Applicant claims the benefit of this earlierprovisional application pursuant to 35 U.S.C. §119(e). The entirecontent of this earlier provisional application is hereby incorporatedherein by this reference.

TECHNICAL FIELD OF THE INVENTION

This invention relates to molten metal reactors for treating wastematerials and soils contaminated with waste materials. Moreparticularly, the invention relates to a molten metal reactor having animproved arrangement for entraining or entrapping feed materials with amolten reactant metal to effect the desired chemical reduction of thefeed material. The invention encompasses a molten metal reactorapparatus, a structure for introducing a feed material into such areactor, a method for treating waste material with a molten metal, and amethod for introducing a feed material into a molten metal reactor.

BACKGROUND OF THE INVENTION

Molten metal reactors utilize a molten reactant metal to chemicallyreact with a feed material in order to reduce the feed material torelatively innocuous compounds and chemical elements. For example, U.S.Pat. No. 5,000,101 to Wagner discloses a molten metal reactor fortreating chlorinated hydrocarbons and other dangerous organic chemicalsto produce carbon, metal salts, and gases such as nitrogen and hydrogen.U.S. Pat. No. 5,271,341 to Wagner discloses a molten metal reactor fortreating boxed biomedical wastes which may include hazardous biologicalwastes mixed with other materials and metals. The disclosed moltenreactant metal chemically reduces biological materials and other organicmaterials in this waste to carbon, metal salts and elemental gasses.Metals such as stainless steel “sharps” in the waste dissolve or meltinto the reactant metal.

A consistent issue with molten metal reactors is providing the necessarycontact between the material to be treated or reacted, that is, the“feed material,” and the molten reactant metal. U.S. Pat. No. 5,271,341to Wagner discloses submerging the boxed biomedical wastes in thereactant metal bath with a submerging or plunger structure to providethe desired contact between the waste material and the molten reactantmetal. Although the submerging structure works well with certain typesof waste materials, such structures are not well suited for submergingother types of materials. In particular, plunger structures are not wellsuited for use in relatively high-volume waste treatment applications inwhich relatively large quantities of loose or bulk feed materials, suchas contaminated soils, for example, must be processed.

SUMMARY OF THE INVENTION

A molten metal reactor according to the present invention quicklyentrains a feed material in the molten reactant metal and provides thenecessary contact between the molten reactant metal and the feedmaterial to effect the desired chemical reduction of the feed material.The quick entrainment of feed material in the molten reactant metal isaccomplished with a unique feed structure in which the feed material isadded to the reactant metal and then quickly transferred into atreatment chamber together with the molten reactant metal and anyinitial reaction products. A majority of the desired reactions occur inthe treatment chamber. Reaction products and unspent reactant metal arepreferably directed from the treatment chamber to an output chamberwhere reaction products are removed from the reactor. Unspent reactantmetal is then preferably transferred to a heating chamber where it isreheated for recycling through the system.

According to the invention, the feed structure associated with thereactor introduces feed material into the molten reactant metal so thata flow of molten reactant metal immediately carries substantially all ofthe feed material and any initial reaction products into the treatmentchamber. The feed material and reaction products are then trapped in thetreatment chamber preferably by means of a suitable gravity trapstructure. This combination of substantially immediate introduction intothe treatment chamber and trapping in the treatment chamber helps ensurethat the feed material and any intermediate reaction products havesufficient contact with the molten reactant metal to provide the desiredchemical reactions, that is, the substantially complete chemicalreduction of the feed material.

The desired contact with the reactant metal is enhanced according to theinvention by inducing a swirling or vortex flow in the molten reactantmetal in a feed chamber in which the feed material first makes contactwith the molten reactant metal. This swirling flow may be produced inany suitable fashion, including by directing the molten metal into thefeed chamber in an off center position, by driving the molten metal inthe feed chamber with an impeller, or both. Also, a bowl-shaped feedchamber helps facilitate the desired swirling flow.

In order to carry the feed material and any initial reaction productsquickly into the treatment chamber in the flow of molten reactant metal,the feed material preferably comes into contact with the molten reactantmetal in an area adjacent to an inlet to the treatment chamber. An area“adjacent” to the treatment chamber inlet means the area of the surfaceof the molten reactant metal in the feed chamber generally nearest tothe inlet of the treatment chamber. In the form of the invention inwhich a swirling flow is induced in the feed chamber, the feed materialdrops into the molten reactant metal in a central area of the feedchamber, at the center of the swirling flow or vortex, and directlyabove an outlet from the feed chamber/inlet to the treatment chamber.The feed chamber includes an outlet that at least borders the treatmentchamber inlet and more preferably comprises a common opening with thetreatment chamber inlet. By “bordering” the treatment chamber inlet itis meant that the feed chamber outlet is in the immediate vicinity ofthe treatment chamber inlet so that there is only a small distancebetween any point of the feed chamber outlet and any point of thetreatment chamber inlet.

The feed material may include substantially any material or mixture ofmaterials suitable for treatment in a molten metal reactor. Thesematerials include hydrocarbons and halogenated hydrocarbons, low andhigh level radioactive materials, and any other materials that may bechemically reduced in a molten reactant metal such as aluminum,magnesium, or combinations of these metals together with other metals.The invention is particularly suited to treating soils and other bulksolids which have been contaminated with hydrocarbons, halogenatedhydrocarbons, other chemically reducible materials, radioactivematerials, and metals. As used in this disclosure and the accompanyingclaims a “feed material” may comprise any of the above-describedmaterials or combinations of these materials.

It will be appreciated by those skilled in the art of molten reactorsthat the chemical reduction reactions produced by contact with a moltenreactant metal may not immediately reduce a given constituent compoundincluded in a feed material. Rather, many chemical compounds suitablefor treatment with a molten reactant metal may initially react in orwith the metal to produce intermediate reaction products. Theseintermediate reaction products are then further reduced by reaction inor with the molten reactant metal. The reactions continue in the moltenreactant metal until the reduction reactions are substantially complete,leaving only final reaction products. Metals in the feed materialcompounds are generally reduced to their elemental state, carbon isreduced to its elemental state and goes to a gaseous state at thetemperature of the molten reactant metal, halogens form salts witheither metals from the molten reactant metal bath or with metalscontained in the feed material itself. Nitrogen and hydrogen liberatedfrom the reacted compounds escape from the molten metal bath as gases.Minerals included in soil generally remain unreacted in the moltenreactant metal depending upon the makeup of the molten reactant metalbath and its temperature, but may go to a liquid state at thetemperature of the molten metal bath.

As used in this disclosure and the accompanying claims, the term“reaction product” is used to refer to any reaction product produced bytreatment of the feed material with the molten reactant metal, whetherthe reaction product is an initial reaction product subject to furtherreactions in the molten metal or a final reaction product that ischemically stable in the molten reactant metal. The term “reactionproduct” also refers to materials such as quartz that do not chemicallyreact with the molten reactant metal but may be contained in soilcontaminated with materials that do react in the molten reactant metal.Thus, the term “reaction product” means generally any material thatresults from any reaction of a feed material occurring in the moltenreactant metal.

The above-described advantages and features of the invention, along withother advantages and features, will be apparent from the followingdescription of the preferred embodiments, considered along with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view in section showing a molten metal reactorembodying the principles of the invention.

FIG. 2 is a diagrammatic top plan view of the molten metal reactor shownin FIG. 1.

FIG. 3 is a diagrammatic view in section similar to FIG. 1 but showingan alternate form of the feed arrangement.

FIG. 4 is a diagrammatic view in section similar to FIG. 3, showing yetanother alternate feed arrangement according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring particularly to FIGS. 1 and 2, a molten metal reactor 10embodying the principles of the invention includes essentially fourchambers including a bowl-shaped vortex or feed chamber 11, a treatmentchamber 12, an output chamber 14, and a heating chamber 15. Each ofthese chambers is adapted to contain a molten reactant metal indicatedby the reference numeral 16. The level of molten reactant metal 16 infeed chamber 11, output chamber 14 and heating chamber 15 is indicatedby the dashed line in the respective chamber. Molten reactant metal 16is heated to the desired temperature in heating chamber 15 and thentransferred to feed chamber 11. From feed chamber 11, molten reactantmetal 16 flows rapidly into treatment chamber 12 and then exits thetreatment chamber into output chamber 14. From output chamber 14, moltenreactant metal 16 returns to heating chamber 15 for reheating andrecycling through the reactor 10. Reaction products are removed fromreactor 10 through output chamber 14. According to the invention, theflow of molten reactant metal from feed chamber 11 to treatment chamber12 carries feed materials to be treated into the treatment chamber alongwith substantially all reaction products liberated from the feedmaterial on initial contact with the molten reactant metal. Treatmentchamber 12 provides sufficient residence time to completely reactsubstantially all constituents in the feed material.

FIG. 1 in particular indicates that molten metal reactor 10 includesnumerous components that contain or come in contact with molten reactantmetal 16. All components that do come in contact with the moltenreactant metal are either formed from a material which is resistant todamage from the reactant metal or coated with such a protectivematerial. For example, the system of chambers 11, 12, 14, and 15 may becast from a refractory material or may be formed from a base materialwhich is then coated with a suitable refractory or other chemicallyresistant material.

The particular reactant metal utilized in reactor 10 will depend uponthe constituents in the feed material which must be destroyed or removedfrom non-hazardous constituents of the feed material. A preferredreactant metal suitable for use in treating many types of chemicalscomprises an alloy of aluminum as disclosed in U.S. Pat. No. 5,000,101to Wagner, the entire content of which is hereby incorporated in thisdisclosure. However, it will be appreciated that the makeup of reactantmetal 16 may be varied to suit a particular feed material to be treatedin reactor 10 and is not limited to aluminum or aluminum alloys. Also,the temperature of reactant metal 16 may be varied to suit theparticular feed material to be treated.

Reactor 10 is well suited for treating a number of feed materials,including particularly contaminated soils. The soils may be contaminatedwith halogenated hydrocarbons or other organic compounds, metals, andlow-level radioactive materials. Organic compounds are reduced toliberate carbon and hydrogen. Halogens included in organic compoundsgenerally react with elements of the reactant metal to form metal salts,while other materials dissolve or melt into the molten reactant metal orrelease from the reactant metal as a gas. Many radioactive materialsdissolve or melt into the reactant metal 16 where the radioactiveisotopes can be concentrated to the desired level together withradioactive emission absorbing elements. Molten reactant metal andabsorbing metal containing the radioactive isotopes may then be drawnoff to form ingots that can safely store the radioactive isotopes.

In addition to the chamber arrangement shown in FIGS. 1 and 2, thepreferred reactor 10 includes molten metal pumps 20 and 21 shown in FIG.2, and a heater arrangement 22 associated with at least heating chamber15. A feed arrangement 24 is associated with feed chamber 11 fortransferring feed materials into the system. Also, the illustratedreactor 10 includes a reaction product removal arrangement associatedwith output chamber 14. The reaction product removal arrangement isshown generally at reference numeral 25.

Referring to both FIGS. 1 and 2, feed chamber 11 includes an outlet 28generally at the bottom of the feed chamber. Feed arrangement 24 islocated preferably immediately over or above outlet 28. Molten reactantmetal 16 is supplied into feed chamber 11 through an inlet 29. As shownbest in FIG. 2, the preferred form of the invention has inlet 29positioned off-center from a center vertical axis of feed chamber 11 sothat the flow of reactant material into the chamber helps induce aswirling or vortex flow in the feed chamber as will be described furtherbelow. Referring still to FIG. 2, reactant metal 16 collects in a supplychamber 31 prior to flowing into feed chamber 11. This flow may becontinuous or may be on a batch basis. Where reactant metal is releasedinto feed chamber 11 in batches, a suitable valve (not shown) may beassociated with inlet 29. The valve may be closed to allow reactantmetal 16 to collect in supply chamber 31 then may be opened to suddenlyrelease the reactant metal into feed chamber 11.

It will be appreciated that it is possible to eliminate pump 21 andinstead use a moveable crucible or vessel to periodically lift moltenreactant metal from heating chamber 15 and pour the molten metal intosupply chamber 31. This moveable crucible form of the invention may beused to introduce a rapid flow of molten reactant metal into supplychamber and then into feed chamber 11.

The preferred form of the invention produces a vortex or swirling flowin the reactant metal 16 contained in feed chamber 11 as the moltenmetal flows rapidly into the feed chamber and then into treatmentchamber 12. This swirling or vortex flow is indicated by the arrows 32in FIG. 2. In the form of the invention shown in FIGS. 1 and 2, theoff-center molten metal inlet 29, bowl-shaped feed chamber 11, and flowrate of molten reactant metal all combine to provide a vortex inducingarrangement. The swirling flow of reactant metal 16 in feed chamber 11provides a good mixing action to rapidly incorporate or ingest the feedmaterial into the reactant metal. It will be appreciated that theswirling reactant metal or vortex flow of molten reactant metal in feedchamber 11, is not necessary to the present invention but is helpful tothe operation of the present invention. Sufficient reactant metal 16flow rates may be produced to provide the desired waste materialentrainment without inducing a vortex in the reactant metal as it flowsfrom feed chamber 11 into treatment chamber 12. For example, moltenmetal pump 21 may pump molten reactant metal into feed chamber 11 at arate on the order of fifteen thousand (15,000) pounds per minute toproduce high molten metal flow velocities from an appropriately sizedfeed chamber outlet to an appropriately sized treatment chamber inlet.

Feed arrangement 24 is adapted to transfer feed materials into reactor10 while minimizing the amount of oxygen entering the reactor. Feedarrangement 24 includes an elongated chute 35 which is preferablycentered within feed chamber 11 to drop feed material into the center ofvortex or swirling flow, immediately above or adjacent to outlet 28 fromthe feed chamber to treatment chamber 12. The bottom end of feed chute35 may be referred to as a feed material inlet into feed chamber 11.Feed chute 35 includes a purge chamber 36 defined between an upper dumpgate 38 and a lower dump gate 39. A purge gas, in this case flue gasfrom heater arrangement 22 is circulated to the purge chamber throughconduit 40 to purge chamber 36 of oxygen. In operation, lower dump gate39 is held in a closed position sealing a bottom of purge chamber 36while upper dump gate 38 is held open and feed material is loaded intothe purge chamber. Once purge chamber 36 is loaded with feed material,upper dump gate 38 is closed and purge gas is circulated through thechamber to purge the chamber of oxygen. After the chamber issufficiently purged, lower dump gate 39 is opened so that the feedmaterial in chamber 36 drops into the molten reactant metal in feedchamber 11. The opening of lower dump gate 39 to drop feed material intofeed chamber 11 may be coordinated with the release of molten reactantmetal 16 into the feed chamber to create the desired swirling flow andsuction effect as the molten reactant metal flows out of the feedchamber and into treatment chamber 12.

An additional sealing conduit 42 may be associated with the feed chute35 to isolate the area of feed chamber 11 generally above or adjacent tothe feed chamber outlet 28. Additional sealing conduit 42 may be used toensure that the feed material and reaction products flow along with thereactant metal 16 into treatment chamber 12. It will also be noted thatthe top of feed chamber 11 above the level of reactant metal 16 issealed to the atmosphere so that any reaction products that may remainin feed chamber 11 are not released to the atmosphere.

Treatment chamber 12 comprises a tube or conduit extending from the feedchamber outlet opening 28 to output chamber 14. The preferred treatmentchamber 12 also includes a gravity trap 44 having a U-shaped segmentthat helps prevent gases from flowing back into feed chamber 11.Treatment chamber 12 is long enough to provide sufficient residencetime, considering the reactant metal flow rate through the tube, toeffect a substantially complete reaction of materials that are to bedestroyed in the molten metal reactor. Residence times should beapproximately three (3) minutes to effect the desired treatment for mostfeed materials. The flow velocity in treatment chamber 12 may be eight(8) feet per minute.

In order to help maintain the reactant metal 16 at a desired treatmenttemperature in treatment chamber 12, the treatment chamber may belocated immediately adjacent to heating chamber 15 so that heat from theheating chamber is transferred to material within the treatment chamber.Also, although not shown in the drawing, a separate heating system maybe associated with the treatment chamber 12 for maintaining thetemperature of the molten metal at a desired temperature within thetreatment chamber. Any suitable heating system may be used withtreatment chamber 12 including an induction heating system using one ormore electromagnetic field induction coils positioned adjacent to thetreatment chamber.

Although a molten reactant metal level is shown by a dashed line in FIG.1 for chambers 11, 14 and 15, FIG. 1 does not show a molten reactantmetal level in treatment chamber 11. This should not be taken to implythat there will be no gas phase in treatment chamber 12. For many feedmaterials, a distinct gas phase of reaction products will emerge in thetop of treatment chamber 12. However, these reaction products will beheld in close proximity to the surface of the molten reactant metal 16in position to facilitate further reaction of the reaction product ifnot fully reduced. Gaseous reaction products will also bubble up throughmolten reactant metal in the output chamber 14 to allow any furtherreactions possible between the reaction products and molten reactantmetal.

A molten metal reactor within the scope of the present invention mayinclude a feed chamber having an outlet that is separate and distinctfrom an inlet to the treatment chamber in the reactor. However, in thepreferred form of the invention shown in FIGS. 1 and 2, feed chamberoutlet 28 is common with the inlet to treatment chamber 12, that is, thefeed chamber outlet and treatment chamber inlet comprise the sameopening. The outlet from the feed chamber according to the invention atleast borders the inlet to the treatment chamber. This proximity betweenfeed chamber outlet 28 and the inlet to the treatment chamber combinedwith the proximity between the point at which the feed material makesinitial contact with the molten reactant metal 16 and the rapid flow ofmolten reactant metal into treatment chamber 12 ensures that the feedmaterial and even any initial reaction products are carried into thetreatment chamber where the desired reactions may proceed to completion.The residence time for feed materials in the feed chamber after initialcontact with the molten reactant metal should be on the order of ten(10) seconds or less. Residence times in this range will be consideredinsignificant residence times within the scope of the following claims.

Output chamber 14 is connected to receive material exiting an outlet 45of treatment chamber 12. The material which flows into outlet chamber 14includes molten reactant metal 16 remaining after the desired reactionswith the feed material and reaction products from the reaction of thefeed material with the reactant metal. The reaction products may includemolten or gaseous metal salts, gaseous carbon, unreacted solids such asclay particles included in the feed material, metals from the feedmaterial that have dissolved or melted into the reactant metal, andother gases liberated in the various reactions between the moltenreactant metal 16 and the feed material. These other gasses willcommonly include primarily nitrogen and hydrogen.

The reaction product removal arrangement 25 associated with outputchamber 14 includes a skimming system shown generally at referencenumeral 49 and a gas and particulate removal system shown generally atreference numeral 50. A tapping system including tapping line 51 with asuitable valve may also be connected to output chamber 14 for removingheavy molten material or dissolved material that may segregate to thebottom of the output chamber.

Gas and particulate removal system 50 includes a collection hood 54 atthe top of output chamber 14 and an outlet conduit 55. This outletconduit 55 preferably leads to particulate control equipment (PCE) 56such as a bag house or an aqueous scrubber that removes particulatesincluded in, or forming from, the gases exiting output chamber 14through conduit 55. Flue gas from the heater arrangement 22 may bedirected into collection hood 54 through conduit 57 to enhance the flowof gases and particulates out of the system through conduit 55. Thepurge gas from purge chamber 36 may also be directed into conduit 55 toexit the system through particulate control equipment 56.

Skimming system 49 is located at the top of output chamber 14 forremoving solids and light molten materials that segregate to the top ofthe reactant metal 16 in the output chamber. The illustrated skimmingsystem 49 includes an auger 58 which is rotated by a suitable drivedevice 59 to skim material floating at the surface of the moltenreactant metal 16 to the right in FIG. 1 toward an outlet chute 60.Outlet chute 60 leads to an airlock chamber 61 defined between an upperairlock gate 62 and a lower air lock gate 63. In operation, lower gate63 is closed and upper gate is held open while auger 59 skims materialthrough outlet chute 60 and into the airlock chamber 61 above the lowergate. After an appropriate amount of skimmed material has collected inairlock chamber 61, upper gate 62 is closed and lower gate 63 is openedto allow material collected in the air lock chamber to drop into acollection vessel 64. Positive pressure maintained in the collectionhood 54 provided by the heater flue gas helps ensure significant amountsof oxygen does not flow into the reactor 10 as solid material and lightmolten material is removed through airlock chamber 61.

One or more deflectors such as deflector 66 may be associated withoutput chamber 14 to deflect reaction products to the desired locationswithin the outlet chamber and ensure that materials do not inadvertentlyenter heating chamber 15. Deflectors may also be used in outlet chamberto enhance contact with the molten reactant metal and help ensure thatthe desired reactions proceed to completion. That is, deflectors inoutput chamber 14 may be arranged to cause relatively light reactionproducts to follow a tortuous path through the molten reactant metal inoutput chamber 14 before reaching the surface of the molten reactantmetal.

Heating chamber 15 comprises a chamber having a lower portion adapted tocontain a volume of reactant metal and an upper area which is isolatedfrom the feed chamber 11 and output chamber 14. This isolation isrequired in the illustrated form of the invention to accommodate the gasfired burners 70 that make up heating arrangement 22 used to heat thereactant metal 16 within heating chamber 15. Exhaust gas from burners 70exits the upper part of the heating chamber through flue gas stack 71. Aportion of this flue gas is directed to purge chamber 36 and tocollection hood 54 as described above. Although gas fired burners areshown in the illustrated form of the invention, other heating systemssuch as an induction heating system for example, may be employed to heatthe reactant metal 16 in heating chamber 15. Of course, whenelectromagnetic induction heating is used to heat reactant metal 16, aseparate purge gas must be used in connection with feed purge chamber 36and collection hood 54 since the flue gas would not be present.

Proper flow and circulation of molten reactant metal 16 in reactor 10 isimportant to the proper operation of the reactor. In particular, theflow of molten reactant metal 16 from feed chamber 11 to treatmentchamber 12 should be at a sufficient rate to entrain or entrap feedmaterial and substantially any initial reaction products, and causethese materials to be carried or swept into the treatment chamber andultimately into output chamber 14. Minimum flow velocities of moltenreactant metal into treatment chamber 14 will depend upon the fluidproperties of the particular molten reactant metal and the specificgravity and other properties of the feed material. The desired flowrates may be produced using pumps for moving the molten reactant metal.FIG. 2 shows two molten metal pumps in the preferred form of theinvention. Pump 20 pumps molten reactant metal 16 from output chamber 14to heating chamber 15. Pump 21 pumps the heated or reheated moltenreactant metal 16 from heating chamber 15 to feed chamber 11, in theillustrated case through supply chamber 31.

It will be noted from FIG. 1 that the level of molten reactant metal 16in feed chamber 11 may be higher than in heating chamber 15 and outputchamber 14. In this arrangement the molten reactant metal 16 provides ahydrostatic head which helps cause the molten metal to flow from feedchamber 11 into treatment chamber 12 and then into output chamber 14.However, the desired flow rates and vortex or swirling flow may beproduced without the higher molten reactant metal level in feed chamber11. Also, it will be appreciated that the desired flow rates of moltenreactant metal into treatment chamber 14 may be produced without theillustrated molten metal pumps. As discussed above, in alternativearrangements a portion of the molten reactant metal from heating chamber15 may be lifted in a suitable vessel and dumped into feed chamber 11(or into supply chamber 31) in order to produce the desired flow ofreactant metal 16 through the feed chamber and into treatment chamber12. Alternatively, molten reactant metal 16 may be collected in supplychamber 31 and released abruptly to flush feed material from feedchamber 11 into treatment chamber 12.

FIG. 3 shows an alternate vortex inducing arrangement according to theinvention. This alternative form of the invention includes the samepreferably bowl-shaped feed chamber 11, treatment chamber 12, andheating chamber 15 included in the embodiment shown in FIGS. 1 and 2.FIG. 3 is broken to omit other portions of the reactor that areidentical to those set out in FIGS. 1 and 2, and do not involve thealternate vortex inducing arrangement. In the form of the inventionshown in FIG. 3, an impeller 80 is included to help induce the desiredswirling or vortex flow of molten reactant metal in feed chamber 11.Impeller 80 may comprise any suitable impeller device suitable for usein a molten reactant metal. U.S. Pat. No. 4,930,986 shows a suitableimpeller, and is incorporated herein by this reference. The type ofimpeller shown in this patent also forces feed material and moltenreactant metal downwardly in feed chamber 11 toward the outlet totreatment chamber 12. Impeller 80 is driven by drive shaft 81 about avertical axis V aligned generally in the center of feed chamber 11. Asuitable motor and drive device 82 rotates drive shaft 81. Drive shaft81 preferably extends though a protective conduit 84. Conduit 84 helpsprotect drive shaft 81 from feed material entering the reactor throughfeed arrangement 85.

Because the center portion of feed chamber 11 is occupied by theimpeller 80 and supporting structure, feed arrangement 85 differs fromfeed arrangement 24 shown in FIG. 1. Feed arrangement 85 includes anelongated feed chute 86 that extends at an acute angle with respect toaxis V. Feed chute 86 includes upper and lower dump gates 87 and 88respectively to define a purge chamber 89 similar to purge chamber 36shown in FIG. 1. The dump gates purge line 90 and purge chamber alloperate similarly to the corresponding elements shown in FIG. 1 and thuswill not be described further here.

An outlet end 91 of feed chute 86 represents a feed material inlet tofeed chamber 11 and terminates in a sealing or confinement conduit 94similar to the sealing conduit 42 shown in FIG. 1 and functionssimilarly to help confine feed material just to the volume of moltenreactant metal 16 immediately above the feed chamber outlet 28.

The flow rate of molten reactant metal 16 into and out of feed chamber11 may be the same as in the embodiment described with reference toFIGS. 1 and 2. Thus, the flow of molten metal 16 through inlet 29 andthe bowl shape of feed chamber 11 may be sufficient to induce someswirling flow in the feed chamber around axis V. Impeller 80 enhancesthe swirling flow and further helps to submerge and entrain feedmaterial in the molten reactant metal 16 so that the feed material maybe quickly carried in the flow of molten metal into treatment chamber12.

FIG. 4 shows yet another alternate feed arrangement for a reactor withinthe scope of the present invention. This alternative feed arrangementincludes a treatment chamber 12 and heating chamber 15 similar to thosedescribed in FIG. 1. The output chamber 14 and related components arealso similar to those shown in FIG. 1 and are therefore omitted fromFIG. 4.

The alternative feed arrangement shown in FIG. 4 includes a feed chamber95 that is just large enough in diameter to accommodate an impeller 96similar to impeller 80 described above with reference to FIG. 3.Impeller 96 is driven on a shaft 97 by motor 98 and the shaft isprotected by housing 99. Molten reactant metal 16 enters feed chamber 95through inlet 101 which preferably resides near the level of moltenreactant metal maintained in the feed chamber. Impeller 96 is positionedso that it traverses the level of the molten reactant metal 16 in feedchamber 95, and preferably comprises an impeller such as that describedin U.S. Pat. No. 4,930,986 to force materials downwardly along axis V inthe feed chamber. The illustrated preferred positioning of impeller 96also allows the impeller to contact and quickly submerge feed materialsinto the molten reactant metal 16 in feed chamber 95. In otherarrangements within the scope of the accompanying claims, the impellermay be located below the level of molten reactant metal in feed chamber95. In other arrangements within the scope of the invention or set outin the accompanying claim, the impeller may be below the level of moltenreactant metal.

Feed materials enter feed chamber 95 through feed material conduit 104.A suitable feed material pump 105 pumps or forces feed material from afeed material supply vessel 106 through conduit 104 and into feedchamber 95. Feed material pump 105 may comprise a diaphragm pump or anauger type pump for example. This feed material arrangement shown inFIG. 4 is particularly suited for feed materials in the form of looseparticles such as loose soils or feed materials in the form of a slurry.

The pumping arrangement for the feed material obviates the need for thepurge chamber and dump gate arrangement shown in FIGS. 1 and 3. Thepositive pressure provided by pump 105 prevents gasses from exiting feedchamber 95 through feed material conduit 104. A pressure relief line 107with suitable valving may be provided in the top of feed chamber 95 toperiodically remove reaction product gasses or other gasses that mightcollect in the feed chamber. Depending upon the nature of these gasses,the gasses removed through line 107 may or may not be subjected totreatment before release to the atmosphere. In some cases the gasses maysimply be directed through particulate control equipment associated withthe reactor's reaction product removal equipment shown in FIG. 1.

The above described preferred embodiments are intended to illustrate theprinciples of the invention, but not to limit the scope of theinvention. Various other embodiments and modifications to thesepreferred embodiments may be made by those skilled in the art withoutdeparting from the scope of the following claims. For example, the feedpump and feed conduit 104 arrangement shown in FIG. 4 may be replaced bythe feed chute and dump gate arrangement shown in FIG. 3, and the feedchambers 11 shown in FIGS. 1 and 3 may include a relief line similar toline 107 shown in FIG. 4. Also, those skilled in the art will appreciatethat many technical details have been omitted from the diagrammaticrepresentations shown in FIGS. 1 and 2 in order to avoid obscuring theinvention in unnecessary detail. These details such as valves andcontrol systems will be apparent to those of ordinary skill in the artfrom the above description of molten metal reactor 10.

What is claimed is:
 1. A method of operating a molten metal reactor totreat a feed material, the method including the steps of: (a) inducing aflow of molten reactant metal from a feed chamber though a feed chamberoutlet to a treatment chamber; (b) introducing the feed material intothe molten reactant metal at a location adjacent to the feed chamberoutlet; and (c) wherein the flow of molten reactant metal from the feedchamber to the treatment chamber is at a rate sufficient to carryreaction products and feed material from the feed chamber into thetreatment chamber without significant residence time in the feedchamber.
 2. The method of claim 1 wherein the step of introducing thefeed material into the molten reactant metal is performed at a locationimmediately above the feed chamber outlet.
 3. The method of claim 2further including the step of containing the feed material in an areaimmediately above the feed chamber outlet as the feed material fallsinto the molten reactant metal in the feed chamber.
 4. The method ofclaim 1 further including the step of inducing a swirling flow of moltenreactant metal in the feed chamber.
 5. The method of claim 4 furtherincluding the step of introducing the molten reactant metal into thefeed chamber at an offset position to induce the swirling flow in thefeed chamber.
 6. The method of claim 1 further including the step ofdirecting the molten reactant metal through a gravity trap associatedwith the treatment chamber for preventing gasses in the treatmentchamber from flowing back into the feed chamber.
 7. The method of claim1 further including the step of adding heat to the materials in thetreatment chamber.
 8. The method of claim 7 wherein the step of addingheat to the materials in the treatment chamber is performed by a heatingdevice associated with the treatment chamber.
 9. The method of claim 7wherein the step of adding heat to the materials in the treatmentchamber is performed by heat transfer with molten reactant metalcontained in an additional chamber.
 10. The method of claim 1 furtherincluding the step of directing molten reactant metal and reactionproducts from the treatment chamber to an output chamber containing asupply of molten reactant metal, wherein the molten reactant metal andreaction products are directed into the outlet chamber at a level belowthe level of molten reactant metal contained in the output chamber. 11.The method of claim 10 further including the steps of: (a) removingreaction products from the output chamber; (b) transferring the moltenreactant metal from the output chamber to a heating chamber; and (c)adding heat to the molten reactant metal in the heating chamber.
 12. Amethod of introducing a feed material into a molten reactant metal, themethod including the steps of: (a) carrying the feed material andreaction products into a treatment chamber within a flow of moltenreactant metal; and (b) trapping the feed material and the reactionproducts in the treatment chamber together with the molten reactantmetal.
 13. The method of claim 12 further including the step of causingthe feed material to come into contact with the molten reactant metal inan area adjacent to an inlet to the treatment chamber.
 14. The method ofclaim 13 further including a feed chamber connected to the inlet to thetreatment chamber and including the step of introducing the feedmaterial to the molten reactant metal in the feed chamber.
 15. Themethod of claim 14 wherein the inlet to the treatment chamber is at abottom of the feed chamber and including the step of inducing a swirlingflow in the feed chamber.
 16. The method of claim 12 wherein the step oftrapping the reaction products and feed material in the treatmentchamber includes causing the molten reactant metal to flow through agravity trap in the treatment chamber.
 17. The method of claim 12further including the step of adding heat to the molten reactant metalas it flows through the treatment chamber.
 18. A method of operating amolten metal reactor to treat a feed material including materials thatare chemically reduced by a molten reactant metal, the method includingthe steps of: (a) inducing a flow of the molten reactant metal from afeed chamber through a feed chamber outlet to a treatment chamber; (b)introducing the feed material into the molten reactant metal so that thefeed material makes initial contact with the molten reactant metal at alocation adjacent to the feed chamber outlet; and (c) wherein the flowof molten reactant metal from the feed chamber to the treatment chamberis at a rate sufficient to carry reaction products and feed materialfrom the feed chamber into the treatment chamber.
 19. The method ofclaim 18 wherein the step of introducing the feed material into themolten reactant metal is performed at a location immediately above thefeed chamber outlet.
 20. The method of claim 19 further including thestep of containing the feed material in an area immediately above thefeed chamber outlet as the feed material falls into the molten reactantmetal in the feed chamber.
 21. The method of claim 18 further includingthe step of inducing a swirling flow of molten reactant metal in thefeed chamber.
 22. The method of claim 18 further including the step ofdirecting the molten reactant metal through a gravity trap associatedwith the treatment chamber for preventing gasses in the treatmentchamber from flowing back into the feed chamber.
 23. The method of claim1 further including the steps of: (a) directing molten reactant metaland reaction products from the treatment chamber to an output chambercontaining a supply of molten reactant metal; (b) removing reactionproducts from the output chamber; (c) transferring the molten reactantmetal from the output chamber to a heating chamber; and (d) adding heatto the molten reactant metal in the heating chamber.
 24. A method ofintroducing a feed material into a molten reactant metal, the feedmaterial including a material that is chemically reduced by the moltenreactant metal, the method including the steps of: (a) carrying the feedmaterial and reaction products into a treatment chamber within a flow ofmolten reactant metal; and (b) maintaining the feed material and thereaction products in the treatment chamber together with the moltenreactant metal for a period of time sufficient to react substantiallyall of the feed material with the molten reactant metal.
 25. The methodof claim 24 further including the step of causing the feed material tocome into contact with the molten reactant metal in an area adjacent toan inlet to the treatment chamber.